The present invention relates to a feeding aggregate for fuel.
One of such aggregates is disclosed for example in the German patent document DE 197 25 941. These feeding aggregate has a feeding pump which is formed as a side channel pump. It is arranged in a pump chamber formed in a housing and has an impeller which is rotatably driven in the pump chamber. For driving of the pump, a brushless electric motor is provided which has a stator winding and a rotor with permanent magnets as well as a stator and a rotor which alternatingly receive the same. The impeller and the rotor are formed as a one part. The feeding pump has one stage, and the impeller at its both end sides is provided with a rim of vanes with intermediate vane chambers. Two ring-shaped feeding passages are formed in the housing opposite to the vane rim of the impeller. An inlet and an outlet which is offset from the inlet in a peripheral direction of the impeller open correspondingly into the feeding chambers. The vane chambers of the vane rim at the both end sides of the impeller are connected with one another so that during the operation of the feeding pump the fuel to be supplied flows through the impeller. Since the impeller and rotor are formed as one part, the impeller must have a thickness which is determined by the rotor in direction of its rotary axis. Thereby during the throughflow of the impeller, the circulation flow of the fuel to be supplied is substantially distorted.
Accordingly, it is an object of present invention to provide a feeding aggregate of the above mentioned general type, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a feeding aggregate which has a feed pump which is formed as a side channel pump and has a housing, a pump chamber formed in said housing, and an impeller arranged in said pump chamber; an electric motor provided for driving of said impeller and having a stator and a rotor, with said rotor formed of one piece with said impeller, said feed pump having at least one pump stage, a rim of vanes having vane chambers therebetween and provided on at least one end side of said impeller, a partial ring-shaped side passage formed in said housing opposite to said rim of vanes and having an inlet and an outlet spaced from one another in a peripheral direction of said impeller and open into said side passage, said at least one pump stage of said feed pump having said rim of vanes only on one end side of said impeller and having said side passage in said housing opposite to said rim of vanes, said inlet and said outlet of said side passage being arranged at a same end side of said impeller, and said impeller at an end side which is opposite to said vanes being provided with recesses which are at least approximately mirror-symmetrical to said vane chambers and are connected through openings in said impeller with said vane chambers.
In the inventive feeding aggregate the fuel does not flow through the impeller, since for each pump stage it has a rim of vanes only at its one end side, which is located opposite to a feeding passage. With recesses which are arranged on the end side of the impeller opposite to the vane rim, at least partially a compensation of axially oriented forces acting on the impeller during the pressure buildup in the feeding passage is obtained. In particular, each of these recesses is connected through the opening with the opposite vane chamber. A fuel feeding is performed on the end side of the impeller which is opposite to the vane rim.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.